Two sets are disjoint if and only if there is no object that is a member of both sets.Notes:
- Source: KIF Version 3.0 Specification
(<=> (Disjoint ?S1 ?S2) (Empty (Intersection ?S1 ?S2)))
(<=> (Pairwise-Disjoint @Sets) (Forall (?S1 ?S2) (=> (Item@Ol-User%Kif-Lists ?S1 (Listof @Sets)) (Item@Ol-User%Kif-Lists ?S2 (Listof @Sets)) (Or (= ?S1 ?S2) (Disjoint ?S1 ?S2)))))
(Forall (?S) (=> (Not (Empty ?S)) (Exists (?U) (And (Member ?U ?S) (Disjoint ?U ?S)))))